White balance is the process of removing unrealistic color cast from a digital image caused by the color of the illumination. Human eyes automatically adapt to the color of the illumination, such that white will always appear white. Unfortunately, image capture devices (e.g., camera sensors) cannot adapt automatically. Therefore, white balance techniques are needed for image sensors in image capture systems (e.g., a digital camera) to compensate for the effect of illumination.
Automatic white balance (AWB) is an essential part of the imaging system pipeline in image capture systems. Digital still cameras and camera phones, for example, apply AWB techniques to correctly display the color of digital images. The performance of AWB has been a differentiating factor for different camera brands. Accordingly, improvements in AWB are desirable.